Mock azure cli commands with Pester

Question

I have a buch of Azure Cli scripts that I have put inside a powershell function, for example:

function NewAppRegistration($name, $replyUrls, $resourceAccessesFilePath) {   
    $appRegistration = az ad app create `
        --display-name $name `
        --reply-urls $replyUrls `
        --oauth2-allow-implicit-flow true `
        --available-to-other-tenants false `
        -o json | 
    ConvertFrom-Json

    if (Test-Path $resourceAccessesFilePath) {
        $appRegistration = az ad app update `
        --id $appRegistration.appId `
        --required-resource-accesses $resourceAccessesFilePath
    }

    return $appRegistration
}

And I want to mock az ad app create but I have no clue how to proceed and I also don't find any example of how to to that. Of course I could end up creating for every az command my own powershell function and I could mock these functions, but I wonder if it could not be made easier?

Answer 1

To mock a bash command like az or any other kind is:

Mock az {}

For the assertion:

Should -Invoke -CommandName "az" -Exactly -Times 1 -ParameterFilter { 
            "$args" -match "ad app create" -and
            "$args" -match "--display-name $expectedName" -and
            "$args" -match "--reply-urls" -and (-not (Compare-Object $args[6] $expectedReplyUrls)) -and
            "$args" -match "--oauth2-allow-implicit-flow true" -and
            "$args" -match "--available-to-other-tenants false" -and
            "$args" -match "-o json"
        }

This is not documented by Pester and this solution was based on this github issue